Seguindo o tutorial da ALTERA para o MODELSIM

Este tutorial ensina como utilizar o Modelsim para realizar a simulação funcional e também temporal. É requisito para a realização do tutorial o acesso ao software Quartus II e Modelsim ou Modelsim-ALTERA.

PASSO 1

• Ler o tutorial Using ModelSim to Simulate Logic Circuits in VHDL Designs, ou [1]
• Obter os arquivos para realizar o tutorial
• Para usar o ModelSim 10.1d na CLOUD-IFSC abra um terminal e digite:

/opt/altera/13.0sp1/modelsim_ase/bin/vsim

• Para usar o ModelSim 10.1d no LabProg abra um terminal e digite:

/opt/altera/13.0/quartus/modelsim_ase/linux/vsim

PASSO 2 - Functional Simulation with ModelSim

Creating a Project

• To create a project in ModelSim, select [File > New > Project...]

project name = serial_adder,

project location <= <subdiretorio do usuário>/Using_ModelSim/functional

default library name <= tutorial

copy settings field.

click [OK]

• Since the file for this tutorial exists, click Add Existing File and select serial.vhd file.
• Once the file is added to the project, it will appear in the Project tab
• click [Close]

Compiling a Project

Compilation in ModelSim checks if the project files are correct and creates intermediate data that will be used during simulation.

• select [Compile > Compile All]. A green check mark will appear to the right of the serial.vhd file in the Project tab.

Preparing Simulation

• Put Modelsim in simulation mode by selecting [Simulate > Start Simulation...]
• The window to start simulation consists of many tabs. For the purposes of the functional simulation, we only need to look at the Design tab.
• In the Design tab you will see a list of libraries and entities you can simulate. In this tutorial, simulate a entity called serial.
• To select this entity, scroll down and locate the tutorial library and click on the plus (+) sign.
• You will see three entities available for simulation: FSM, serial, and shift_reg. Select the serial entity (Design Unit(s) = tutorial.serial) and click [OK] to begin simulation.

See the equivalent tcl command in Transcript window:

vsim tutorial.serial

• Using the sim tab and the Objects window we can select signals for simulation. To add a signal to simulation, rightclick (with shift key) on the signals names in the Objects window and [select Add > To Wave > Selected Signals]. Add signals A, B, resetn, start, clock, sumfrom serial entity,

add wave  \
sim:/serial/A \
sim:/serial/B \
sim:/serial/start \
sim:/serial/resetn \
sim:/serial/clock \
sim:/serial/sum

• Add signal current_state and counter from my_control component.

add wave  \
sim:/serial/my_control/current_state \
sim:/serial/my_control/counter

• There are two ways to run a simulation in ModelSim: manually or by using scripts. In this tutorial, we perform the simulation manually.

Manual Simulation

• To set the clock period, right-click on the clock signal and select Clock... from the pop-up menu.

[clock period = 100 ps], [first edge = falling edge] and click [OK].

• To reset the circuit, set the resetn signal low by right-clicking on it and selecting the Force... from the pop-up menu.

[Value = 0] and [OK].

• Set the value of the start signal to 0.

[Value = 0] and [OK].

force -freeze sim:/serial/clock 0 0, 1 {50 ps} -r 100
force -freeze sim:/serial/resetn 0 0
force -freeze sim:/serial/start 0 0

• To run a simulation for 100 ps, set the value in the text field to 100 ps (default) and press the [Run] button.

run 

• To test the serial adder we will add numbers A=143 and B=57 => sum=200.
• To specify a value for A (B) in decimal, right-click on it, and choose Force... from the pop-up menu.

A [Value = 10#143] and [OK].

B [Value = 10#57] and [OK].

• Set resetn to 1 to stop the circuit from resetting. Then set start to 1 to begin serial addition,

force -freeze sim:/serial/A 10#143 0
force -freeze sim:/serial/B 10#57 0
force -freeze sim:/serial/start 1 0
force -freeze sim:/serial/resetn 1 0

• Change the radix of A and B signal. Highlight them in the simulation window, click right, and select [Radix > Unsigned]. Change the radix of the sum and counter signal to unsigned as well.
• To complete the operation, the circuit will require 10 clock cycles. run 1000 ps using the Transcript command.

run 1000 ps [enter] (or)
run 1000 [enter]

Simulation with do file

• Create a do file with all the transcript commands. [File > New > Open > Do] and [File > Save As...] serial_adder.do

# Preparing Simulation
vsim tutorial.serial
# Adding signal to wave
add wave  \
sim:/serial/A \
sim:/serial/B \
sim:/serial/start \
sim:/serial/resetn \
sim:/serial/clock \
sim:/serial/sum
add wave  \
sim:/serial/my_control/current_state \
sim:/serial/my_control/counter
# Defining clock and inicial reset and start value
force -freeze sim:/serial/clock 0 0, 1 {50 ps} -r 100
force -freeze sim:/serial/resetn 0 0
force -freeze sim:/serial/start 0 0
# Simulation of 1 clock periods
run 100
# Defing A = 143 and B = 57
force -freeze sim:/serial/A 10#143 0
force -freeze sim:/serial/B 10#57 0
# Redefining reset and start value
force -freeze sim:/serial/start 1 0
force -freeze sim:/serial/resetn 1 0
# Simulation of 10 clock periods 
run 1000

• If needed restart the simulation

restart -force

• type in transcript command

do serial_adder.do

• Change the radix of A, B, sum and counter signal to unsigned. There is no tcl command for this.